U.S. patent application number 14/006368 was filed with the patent office on 2014-01-09 for device for applying electrode assemblies.
The applicant listed for this patent is Guenter Edlinger, Christoph Guger. Invention is credited to Guenter Edlinger, Christoph Guger.
Application Number | 20140012123 14/006368 |
Document ID | / |
Family ID | 45851331 |
Filed Date | 2014-01-09 |
United States Patent
Application |
20140012123 |
Kind Code |
A1 |
Guger; Christoph ; et
al. |
January 9, 2014 |
DEVICE FOR APPLYING ELECTRODE ASSEMBLIES
Abstract
The invention relates to a device comprising a number of
electrode assemblies (10), which can be applied to the skin surface
(4) of an animal or human being and by means of which voltages and
currents can be tapped from the skin surface (4), and comprising a
flexible, in particular extendable, retaining element (6) formed by
a planar or film-like molded part. According to the invention, the
electrode assemblies (10) comprise a main body (1) and a number of
pin electrodes (2) that protrude from the main body (1) in the same
direction, the electrode assemblies (10) are fastened to the
retaining element (6), and the main body (1) of the respective
electrode assembly (10) is connected to the retaining element (6),
wherein the pin electrodes (2) of all electrode assemblies (10)
protrude in the same direction.
Inventors: |
Guger; Christoph;
(Piberbach, AT) ; Edlinger; Guenter; (Graz,
AT) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Guger; Christoph
Edlinger; Guenter |
Piberbach
Graz |
|
AT
AT |
|
|
Family ID: |
45851331 |
Appl. No.: |
14/006368 |
Filed: |
January 31, 2012 |
PCT Filed: |
January 31, 2012 |
PCT NO: |
PCT/AT2012/000014 |
371 Date: |
September 20, 2013 |
Current U.S.
Class: |
600/393 |
Current CPC
Class: |
A61B 5/6814 20130101;
A61B 5/0478 20130101; A61B 2562/046 20130101; A61B 5/6803 20130101;
A61B 5/04085 20130101 |
Class at
Publication: |
600/393 |
International
Class: |
A61B 5/0408 20060101
A61B005/0408; A61B 5/0478 20060101 A61B005/0478 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 21, 2011 |
AT |
A 402/2011 |
Claims
1. A device with a plurality of electrode assemblies (10) which may
be applied to the surface of the skin (4) of an animal or a human
being, and by which electrode assemblies voltages and currents may
be tapped from the skin surface (4), which device further has a
flexible, particularly extendable, cover (6) which is formed with a
flat or film-like moulded piece, wherein the electrode assemblies
(10) each have a main body (1) and a plurality of pin electrodes
(2) which protrude in the same direction from the main body (1),
and the electrode assemblies (10) are attached or connected to the
retaining element (6), the main body (1) of a respective electrode
assembly (10) is connected to the retaining element (6), and the
pin electrodes (2) of all of the electrode assemblies (10) protrude
in the same direction; characterized in that the pin electrodes (2)
are arranged on a common electrode ring (14) and are electrically
conductively connected with said ring, wherein the electrode ring
(14) is preferably comprised of the same material as the pin
electrodes (2).
2. The device according to claim 1, characterized in that a
pervasive recess (3) is provided in the main body (1) of one
electrode assembly (10) and particularly of all electrode
assemblies (10), through which recess a gel (5) may be applied to
the skin surface (4), when the pin electrodes (2) are applied
against the skin surface (4), which gel reduces the contact
resistance between the skin surface (4) and the pin electrodes
(2).
3. The device according to claim 2, characterized in that the
retaining element (6) has recesses (62) the position of each of
which is adapted to the position of one of the recesses (3) in the
main body (1), so that a gel (5) may be applied to the skin surface
(4) through the recesses (62) in the retaining element (6) and
through the recess (3) in the respective main body (1).
4. The device according to claim 2, characterized in that the main
bodies (1) of the electrode assemblies (10) are flat or
plate-shaped with two surface regions (11, 12), opposite to each
other, wherein the recesses (3) in the main bodies (1) are
pervasive recesses, and the boundaries (31) of the recesses (3)
connect the two surface regions (11, 12) of the main body (1) with
each other, respectively.
5. The device according to claim 1, characterized in that the pin
electrodes (2) are fixed to the boundary of the recess (3) on the
main body (1).
6. The device according to claim 1, characterized in that the
recess (3) in the electrode assembly (10) is circular.
7. The device according to claim 1, characterized in that in each
instance, any two adjacent pin electrodes (2) of an electrode
assembly (10) are separated by the same distance.
8. The device according to claim 1, characterized in that the
number, arrangement, and height or length of the pin electrodes (2)
are such that the pin electrodes may penetrate through hair on the
skin surface (4) and can provide a stable application, and/or in
that the height of the pin electrodes (2) is between 1 and 30
mm.
9. The device according to claim 1, characterized in that the area
of the main body (1) which is excised by the respective recess (3)
of the electrode assembly (10) is from 0.785 to 700 mm.sup.2,
and/or the radius of the recess (3) is between 1 and 30 mm.
10. The device according to claim 1, characterized in that the
diameter of the pin electrodes (2) is selected such that the pin
electrode (2) may penetrate through the hair on the skin surface
(4) but does not hurt the skin surface at a contact pressure which
allows an electrical contact and/or that the diameter of the pin
electrodes (2) is between 0.5 and 5 mm.
11. The device according to claim 3, characterized in that the ends
of the pin electrodes (2) which are distal from the main body (1)
are hemispherical.
12. The device according to claim 1, characterized in that the pin
electrodes (2) are highly conductive, and in particular are
comprised of gold, TiN, or an alloy comprised of gold and/or TiN
and/or IrO.sub.2.
13. The device according to claim 1, characterized in that,
particularly on the main body of a respective electrode assembly
(10), an amplifier device (13) is provided or arranged,
particularly at a distance of less than 20 mm from the closest pin
electrode (2), and the pin electrodes (2) are connected to the
amplifier device (13).
14. The device according to claim 1, characterized in that the
amplifier device (13) is arranged on a separate, further main body
(15) which is releasably electrically and mechanically connected to
the respective main body (1), particularly via catch connections
(16, 19, 19a).
15. The device according to claim 16, characterized in that the
retaining element (6) has a plurality of recesses (62), and the
catch connections (19, 19a) extend through the recesses (62) of the
retaining element (6).
Description
[0001] The invention relates to a device for applying electrode
assemblies to the surface of the skin of an animal or human being,
according to the independent claim 1.
[0002] In the following the animal or human at whose skin voltages
or voltage differences are to be determined will be referred to as
the "patient".
[0003] The inventive electrode assemblies are used in particular in
the medical field for measuring brain currents or cardiac
activity.
[0004] In the use of dry electrodes for detecting electrical
signals in the interior of the body of the patient, correct
positioning of the electrodes is an essential requirement.
According to the state of the art, so-called spiders are used which
fix the individual electrodes or electrode assemblies to the body
part of the patient on which measurements are to be made, to
provide maximal holding and problem-free contact of the
electrodes.
[0005] Spiders have a plurality of arms on the ends of which
individual electrodes are arranged. A problem with this is that the
positions and orientation of the individual electrodes have to be
adjusted to the particular form of the patient, and therefore
numerous different adjustment steps have to be carried out in order
to adapt the electrodes to the patient. A further problem is that
the electrodes are only poorly in contact with the patient and may
easily slip out of place if the patient moves.
[0006] The object of the invention is to make possible a simplified
adaptation of the individual electrodes to the shape of the body,
particularly of the head, of the patient, and thereby allow more
rapid progress in studying multiple patients.
[0007] This object is achieved according to the invention by a
device for applying electrode assemblies to the surface of the skin
of an animal or human, having the features of the predicate of the
independent claim 1.
[0008] In a device with a plurality of electrode assemblies which
may be applied to the surface of the skin of an animal or human and
with which voltages and currents from the skin surface may be
tapped, which device has a retaining element which is a flexible,
particularly extendable flat or film-like moulded piece, it is
provided according to the invention that the electrode assemblies
each have a main body as well as a plurality of pin electrodes
which protrude in the same direction from the main body, and the
electrode assemblies are attached to the retaining element, further
that the main body of a respective electrode assembly is connected
to the retaining element, the pin electrodes of all of the
electrode assemblies protruding in the same direction. This thereby
allows simple positioning of the electrodes as well as simple
adaptation of the positions of the electrodes on the respective
patient.
[0009] In order to improve the adaptation to special body parts, it
may be provided that the retaining element is in the form of a
cover or a sleeve.
[0010] It may further be provided that a pervasive recess is
provided in the main body of at least one of the electrode
assemblies and particularly of all the electrode assemblies,
through which recess a gel may be applied to the skin surface, when
the pin electrodes are applied against the skin surface, which gel
reduces the contact resistance between the skin surface and the pin
electrodes.
[0011] It is thereby possible to achieve improved contact of the
pin electrodes with the skin surface of the patient, thereby
minimising the influence of movements of the patient during the
measurement. Moreover there is the advantage that if the contact is
sufficiently good it is possible to omit the use of a gel, thereby
avoiding soiling of the patient with the gel. If it is possible to
do without the use of a gel because of sufficient contact, a
time-consuming application of gel is not required.
[0012] In order to facilitate the application of gel to the
respective skin locations during measurement, it may be provided
that the retaining element has recesses, the respective position of
which is adapted to the position of each of the respective recesses
in the main body, so that a gel may be applied to the skin surface
through the recesses in the retaining element and through the
recess in the main body.
[0013] In order to achieve particularly good application to the
body of the patient, particularly in measurements of longer
duration, it may be provided that the main body is flat or
plate-shaped with two opposite surface regions, wherein the recess
is a pervasive recess, and the boundary of the recess connects the
two surface regions with each other.
[0014] For advantageous application of a gel to the pin electrodes
and for reducing the contact resistance between the pin electrodes
and the skin surface, it may be provided that the pin electrodes
are fixed to the boundary of the recess on the main body.
[0015] For optimum distribution of the applied gel, it may be
provided that the recess is circular.
[0016] Further, in order to improve the application stability of
the electrode assembly to the skin of the patient, it may be
provided that any two adjacent pin electrodes are separated by the
same distance.
[0017] In order to achieve improved contacting of the pin
electrodes and to reduce transmission errors, it may be provided
that the pin electrodes are arranged on a common electrode ring,
wherein the electrode ring is preferably comprised of the same
material as the pin electrodes.
[0018] For advantageous penetration of the hair on the surface of
the skin, and to achieve an advantageous application stability of
the electrode assembly on the skin of the patient, it may be
provided that the number, arrangement, and height or length of the
pin electrodes are such that the pin electrodes may penetrate
through hair on the skin surface and may provide a stable
application; and/or that the height of the pin electrodes is
between 1 mm and 30 mm.
[0019] For advantageous distribution of the gel on the skin
surface, it may be provided that the area occupied by the surface
of the main body of an electrode assembly which is excised to form
the recess is from 0.785 to 700 mm.sup.2, and/or the radius of the
recess is between 1 mm and 30 mm.
[0020] In order to improve the contact between the skin surface and
the pin electrodes, and to improve the mechanical application
stability, it may be provided that the diameter of the pin
electrodes is selected such that the pin electrode may penetrate
through the hair on the skin surface but does however not hurt the
skin surface at a contact pressure allowing electrical contact;
and/or that the diameter of the pin electrodes is between 0.5 and 5
mm.
[0021] In order to improve the contact between the skin surface and
the pin electrodes, and to avoid injury to the patient, it may be
provided that the ends of the pin electrodes which are distal from
the main body are hemispherical.
[0022] For durable electrical contacting and reduction of the
contact resistance and contact voltage, it may be provided that the
pin electrodes are highly conductive, and in particular are
comprised of gold, TiN, IrO.sub.2, or of an alloy comprised of gold
and/or TIN, IrO.sub.2.
[0023] In order to avoid electrical disturbances, e.g. due to
electromagnetic interference, it may be provided that an amplifier
assembly is provided and the pin electrodes are connected to the
amplifier assembly. In this way, operation is possible even in the
case of high skin resistance.
[0024] When the amplifier assembly is arranged on the main body,
this enables simplified contacting of the electrodes.
[0025] Optimal amplification with minimum noise is possible when
the maximum distance of the amplifier assembly to the closest pin
electrode is less than 20 mm.
[0026] To facilitate easy exchangeability of electrodes as well as
to reduce the number of amplifier assemblies, it may be provided
that the amplifier assembly is arranged on a separate further main
body which is electrically and mechanically removable and
connectable to the main body, in particular through catch
connections.
[0027] In order to guarantee a simple structure of the device
according to the invention and rapid replacement of defective
electrodes and replacement of amplifiers on further main bodies, it
may be provided that the retaining element has a plurality of
recesses, and the catch connections extend through the recesses of
the retaining element.
[0028] The invention will be described with reference to a number
of examples, with reference to the appended drawings, without
limiting the general inventive concept.
[0029] FIGS. 1a and 1b show two illustrations of an electrode
assembly from different viewpoints. FIG. 1c shows the electrode
assembly in cross-section. FIG. 2a illustrates a side view of a
separately formed amplifier circuit on a further main body which is
contacted with the electrode assembly illustrated in FIGS. 1a to
1c. FIG. 2b shows a cross-section of the arrangement shown in FIG.
2a. FIG. 3a illustrates a cover with an electrode assembly and
interior. FIG. 3b illustrates the cover shown in FIG. 3a from the
exterior. FIG. 4 illustrates a portion of a device for application
against the skin surface, applied against a patient, in
cross-section.
[0030] FIG. 5 illustrates an alternative electrode assembly
according to the invention. FIG. 8 illustrates a separate amplifier
circuit formed on a circuit board, which is contacted with an
electrode assembly. FIG. 7 illustrates a cover with a plurality of
electrode assemblies. In FIG. 8, part of a device for application
against the skin surface, applied to a patient, is shown in
cross-section.
[0031] In FIGS. 1a to 1c, an embodiment of an electrode assembly 10
is illustrated. This comprises a main body 1 in the form of a
circuit board. The main body 1 is essentially flat and has a
thickness of 1.2 mm. The two surface areas 11 and 12 opposite to
each other of the main body 1 are flat and parallel with each
other. The main body 1 is circular.
[0032] In the region of the boundary of the circular main body 1,
eight pin electrodes 2 are arranged which protrude from one of the
surface regions 11. The number of such electrodes 2 is
advantageously more than 3, to facilitate a mechanically stable
application to the skin surface 4 of the patient 7 (FIGS. 4, 8). On
the other hand, the number of electrodes 2 is selected such that
sufficient distance is provided between the electrodes 2 to receive
hairs, so that individual hairs of the patient 7 do not become
caught between the electrodes 2 and the skin surface 4. The
distance between two adjacent electrodes 2 is approximately twice
the diameter of an electrode 2.
[0033] In the present embodiment, the pin electrodes 2 have a
length of 7 mm and a diameter of 2.5 mm. The distal ends of the
electrodes 2 have a hemispherical shape.
[0034] In the present embodiment, the pin electrodes 2 are
comprised of pure gold, with a minimum of impurities.
[0035] Alternatively, however, other alloys may however be used;
wherein, advantageously, the pin electrodes 2 have low electrical
resistance. It is further advantageous if the pin electrodes 2 have
high mechanical stability, particularly flexural strength and
breaking strength, e.g. as is typically the case with alloys of TIN
or IrO.sub.2.
[0036] The main body 1 has an electrically highly conductive
electrode ring 14 in its boundary region and in its area facing
away from the pin electrodes 2, which ring is comprised of a gold
alloy and is soldered to the pin electrodes 2. In the present
embodiment, the electrode ring 14 forms a part of the main body 1
and has the form of a hollow cylindrical layer with a layer
thickness of 1.2 mm, an inner radius of 11 mm, and an outer radius
of 17 mm. The part 14a arranged in the interior of the main body 1
and surrounded by the electrode ring 14 is not conductive.
[0037] Alternatively, the entire main body 1 may be comprised of
highly conductive material, particularly electrode material.
[0038] Alternatively, the pin electrodes 2 may be welded or
otherwise electrically conductively and mechanically connected to
the electrode ring 14.
[0039] On the surface region 12 opposite to the surface region 11
from which the pin electrodes protrude, a connecting piece 19 is
provided which is conductively connected to the electrode ring and
thus with the individual pin electrodes 2. In the present case the
connecting piece 19 is in the form of a catch piece which may be
removably connected to a further connecting piece 19a (FIGS. 2a,
2b). The connecting piece 19 is also comprised of a material with
good conductivity, in order to advantageously pass on the signals
determined by the pin electrodes 2.
[0040] In FIGS. 2a and 2b the electrode assembly 10 illustrated in
FIGS. 1a to 1c is electrically and mechanically connected via the
connecting piece 19 to a further main body 15 which has a further
connecting piece 19a which is electrically and mechanically
connectable with the connecting piece of the electrode
assembly.
In this way, a two-piece electrode assembly is illustrated having
the illustrated main body 1 as well as the structure of the pin
electrodes 2 corresponding to the embodiment illustrated in FIGS.
1a to 1c. An amplifier assembly 13 is arranged on the further main
body 15. The main body 1 and the further main body 15 are
electrically conductively interconnected by the respective
connecting pieces 19 and 19a, with the further main body having a
connecting line 18 between the further connecting piece 19a and the
amplifier 13. The catch connection between the main body 1 and the
further main body 15 is releasable and restorable without suffering
any mechanical damage. The output signal of the amplifier 13 is
transmitted via a cable 13a to a data processing unit.
[0041] In FIGS. 3a and 3b a retaining element 6 in the form of a
cover 61 is shown, from the inside and from the outside, with only
one electrode assembly 10 and one further main body 15 being shown.
The cover 61 is designed for application to the surface of the skin
4 on the head of a patient 7. The electrode assemblies 10
essentially correspond to the electrode assemblies 10 illustrated
in FIGS. 2a and 2b. The main body of the electrode assemblies 10
lies against the inner side of the cover 61, with the further
surface region 12 being in physical contact with the inner surface
of the cover 61. The pin electrodes 2 extend into the interior of
the cover 61. The cover 61 has recesses 62 in the regions of the
catch connections 16 of the electrode assemblies 10, which recesses
allow direct contacting with the further main body 15 (FIG. 4), so
that the skin surface of the patient is directly electrically
contactable through the cover 61.
[0042] The further main body 15 is on the outer side of the cover
61, wherein the side toward which the further connecting piece 19a
is directed, is directed toward the cover 61, and is in electrical
and mechanical contact with the connecting piece 19 which passes
through the recess 62 in the cover.
[0043] In FIG. 4, the embodiment of the invention illustrated in
FIGS. 3a and 3b is shown in cross section. The cover 62 has, as
shown in FIGS. 3a and 3b, a plurality of electrode assemblies 10
arranged on its inner surface. The recesses 62 in the sleeve 63 are
penetrated by the connecting piece 19 and 19a of the main body of
the electrode assembly 10 and of the further main body.
[0044] An intermediate region filled with hairs between the skin
surface 4 and the main body 1 is shown hatched, designated
subsequently by "hair region 72". The main body 1 and the skin
surface 4 of the patient 7 are held apart by the hair as well as by
the pin electrodes 2.
[0045] FIG. 5 illustrates an alternative embodiment of an electrode
assembly 10. This is comprised of a main body 1 in the form of a
circuit board. The main body 1 is essentially flat, with thickness
of 1.2 mm. The two surface regions 11 and 12 opposite to each other
of the main body 1 are planar and parallel. A circular recess 3 is
formed in the main body 1. In this preferred embodiment of the
invention, the diameter of the recess 3 is 5 mm, and thus the
radius is 2.5 mm. The recess 3, i.e. the excised surface of the
main body 1 has an area of approximately 50 mm.sup.2.
[0046] In the region of the boundary of the recess 3 there are
seven pin electrodes 2 which protrude from one of the surface
regions 11. Advantageously, the number of pin electrodes 2 is more
than three, to facilitate a mechanically stable application to the
skin surface 4 (FIG. 8) of the patient 7 (FIG. 8). On the other
hand, the number of pin electrodes 2 is selected such that there is
sufficient space between the pin electrodes 2 to receive hairs and
to avoid a situation where individual hairs of the patient 7 become
stuck between the pin electrodes 2 and the skin surface 4. The
distance between adjacent pin electrodes 2 is approximately the
diameter of a pin electrode 2.
[0047] In the present embodiment, the pin electrodes 2 have length
7 mm and diameter 2.5 mm. The ends of the pin electrodes 2 which
are distal from the main body 1 have a hemispherical shape.
[0048] In the present embodiment, the pin electrodes are comprised
of pure gold with a minimum of impurities.
[0049] Alternatively, however, other alloys may be used, wherein
advantageously the pin electrodes 2 may have low electrical
resistance. It is further advantageous if the pin electrodes 2 have
high mechanical stability, particularly flexural strength and
breaking strength, e.g. as is typically the case with alloys of
TiN.
[0050] The main body 1 has in the region of the recess 3 an
electrically highly conductive electrode ring 14 comprised of a
gold alloy, to which the pin electrodes 2 are soldered. The
electrode ring 14 has a square cross section of 10 mm.times.10 mm.
The radius of the recess in the interior of the electrode ring 14
is 5 mm, and the area of the recess is 50 mm.sup.2. Alternatively,
the pin electrodes may be connected to the electrode ring 14 by
welding or by other electrically conducting and mechanical means.
The electrode ring 14 passes through the entire main body 1,
wherein the surface extending in the direction of the central
recess of the electrode ring 14 forms a boundary of a cylinder
barrel form 31 of the recess 3 extending perpendicularly to the
surface regions 11 and 12. The electrode ring 14 is connected to an
amplifier assembly 13 (FIG. 8) by a highly electrically conductive
connecting line arranged on the further surface region 12 (not
shown in FIG. 5). Advantageously, in this embodiment this
electrical connecting line is comprised of the same electrode
material as the pin electrodes 2.
[0051] The amplifier assembly 13 is close to the individual pin
electrodes, and in the present embodiment, for the purpose of
minimising electromagnetic disturbances, the device 13 is arranged
4 mm away from the nearest pin electrode 2.
[0052] FIG. 6 illustrates an alternative two-piece electrode
assembly 10, wherein the main body 1 as well as the arrangement of
the pin electrodes 2 corresponds to the embodiment illustrated in
FIG. 5. Unlike the embodiment illustrated in FIG. 5, the main body
of the alternative illustrated in FIG. 6 has a further main body 15
on which the amplifier assembly 13 is arranged. The main body 1 and
the further main body 15 are electrically conductively connected
via respective connecting lines 17 and 18 on the main body 1 and on
the further main body 15, and via a catch connection 16. The catch
connection 16 enables releasable mechanical connection of the main
body 1 and the further main body 15.
[0053] In the present embodiment, the electrical connecting lines
17 and 18 are in the form of connecting layers on the surfaces of
the main bodies 1 and 15.
[0054] In FIG. 7 a retaining element 6 in the form of a cover 61,
for being applied against the surface of the skin 4 on the head of
a patient 7 is illustrated. The electrode assemblies 10 essentially
correspond to those illustrated in FIG. 5. The main bodies 1 of the
electrode assemblies 10 lie on the interior of the cover 61,
wherein the additional surface area 12 is in mechanical contact
with the inner surface area of the cover 61. The pin electrodes 2
extend into the interior of the cover 61. In the regions in which
the recesses 3 of the electrode assemblies 10 are arranged, the
cover 61 has recesses 62, so that a gel 5 (FIG. 8) may be applied
directly from the exterior through the cover 61 and onto the skin
of the patient 7. In the embodiment illustrated in FIG. 7, for
example, this can readily occur because the recesses 62 of the
cover 1 are aligned with the recesses 3 of the main body 1 of the
respective electrode assembly 10.
[0055] Alternatively, however, it is also possible for the
individual electrode assemblies 10 to be inserted into individual
recesses 62 of the cover 61, with the cover 61 continuing in the
region of its recess 62. In this case, the outer boundary of the
electrode assembly 10 adjoins the inner boundary of one of the
recesses 62 of the cover 61.
[0056] In FIG. 8 a part of a different embodiment of the invention
is shown, in the form of a sleeve 63 which is in operation with the
patient 7. The sleeve 63 has, similarly to the cover 61 shown in
FIG. 7, a plurality of electrode assemblies 10 arranged on its
inner surface. The recesses 62 in the sleeve 63 are aligned with
the recesses 3 in the main body 1 of the electrode assembly 10, so
that a gel 5 may be applied to the skin surface 4 of the patient 7.
After the gel 5 is applied through the recess 3 it is arranged in
the intermediate region filled with hair (indicated by hatched
lines), hereinafter referred to as the hair region 72, between the
skin surface 4 and the main body 1. The main body 1 and the skin
surface 4 of the patient 7 are separated by the hair on the one
hand and by the pin electrodes 2 on the other hand. The gel 5
diffuses into the hair region 72 and reaches the application points
8 of the pin electrodes 2 against the skin surface 4, used for
substantially reducing the contact resistance.
[0057] In a case when there is already sufficient electrical
contact and signals of sufficient quality for the respective study
are available, the application of the gel 5 to the skin surface 4
in the hair region 72 may be omitted.
[0058] Alternatively to the gel 5, an aqueous foam or a wet sponge
(neither illustrated) may be used, to be arranged in the recess 3
of the main body 1 and between the pin electrodes 2.
[0059] In order to prevent moisture or water from penetrating into
the electrode assembly 10, the electrically active components of
the electrode assembly 10 such as, e.g., the amplifier assembly 13,
may have a waterproof design. The output signal of the amplifier 13
is transmitted by a cable (not shown in FIGS. 5 to 8) to a data
processing unit.
[0060] Alternatively, it may be provided that the pin electrodes 2
are not comprised entirely of gold and/or TiN and/or IrO.sub.2 or
an alloy of gold and/or TiN and/or IrO.sub.2, but rather of a
supporting body, e.g. comprised of metal, which is only coated with
one of the indicated highly conductive alloys.
* * * * *